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MATH 1030-004, Quiz 2 Solution Spring 2014 1. (4 pts) John’s weekly take-home pay (after taxes) is $675. If he pays 23% of his gross pay (before taxes) in tax, what is his gross pay? $675 = (1 − 0.23) · x ⇒ x = $675 = $876.62. 0.77 2. Express the first number as a percentage of the second. (a) (2 pt) 220 men at a conference with 430 people. 220 = 0.5116 = 51.16%. 430 (b) (2 pt) 145 Subarus in a parking lot with 436 cars. 145 = 0.3326 = 33.26%. 436 3. In the past four decades, the five-year survival rate for all forms of cancer increased from 36% to 63%. What is (a) (2 pt) the absolute change? Absolute Change = 63 − 36 = 27 percentage points. (b) (2 pt) the relative (percentage) change (in terms of a percentage)? Relative Change = 1 27% = 0.75 = 75%. 36% 4. (4 pts) Write each of the following numbers in scientific notation. (a) 0.011 = 1.1 · 10−2 (b) 225, 500 = 2.255 · 105 (c) 400.51 = 4.0051 · 102 (d) 0.001002 = 1.002 · 10−3 5. (Extra Credit: 4 pts) Find the scale ratio for the map where 1 foot on the map represents 250 meters on the ground. (1 m = 3.28 ft.) 250 m · 3.28 ft = 820 ft. 1m Therefore, the scale ratio is 1 : 820, or 1 to 820. 2